Genesis 46:18

(18) Sixteen souls.—That is, Gad and his seven sons, Asher and his four sons, the two grandsons and Serach.

A Bible Commentary for English Readers, edited by Charles John Ellicott (1878–1897) — public domain. Text from a community e-Sword module.

And the sons of Benjamin,.... The second son of Jacob by his wife Rachel; whose sons

were Belah, and Becher, and Ashbel, Gera, and Naaman, Ehi, and Rosh,

Muppim, and Huppim, and Ard; in all one hundred and ten. It is a difficulty to account for it, that Benjamin, Jacob's youngest son, often called a lad at this time, and generally supposed to be about twenty three or four years of age, should have so many sons: some think he had more wives than one, which is not likely, since we never read of any of Jacob's sons that had more than one at a time; and others, that his sons were born twins, and so had them in a little time, which is a much better solution of the difficulty: but others are of opinion, that though the greater part of them might be born in Canaan, yet others might be born in Egypt; and being denominated from the greater part, and that being put for the whole, may be reckoned among the descendants into Egypt; and even those that were in Egypt, being born while Jacob was alive, might be said to descend there in his loins; which may be the best of the ways proposed for removing this difficulty: though I should rather think they were all born before the descent into Egypt, the whole narrative seems to require this of them all; for otherwise many more might be, said to descend in the loins of Jacob, or in the loins of his sons, which would greatly increase the number of those said to go down with him, after mentioned: to which it may be added, that Benjamin was at least thirty two years of age, and so may very well be thought to have had these children before he went to Egypt.

John Gill's Exposition of the Whole Bible (1746–1763) — public domain (CC PDM 1.0). Text via the HelloAO Bible API.

These arc the sons of Zilpah, whom Laban gave to Leah his daughter, and these she bare unto Jacob, even sixteen souls.

The Pulpit Commentary (1880–1919), ed. H.D.M. Spence-Jones & Joseph S. Exell — public domain. Text from a community e-Sword module.

THESE ARE THE SONS OF ZILPAH, etc. 19. THE SONS OF RACHEL JACOB’s WIFE, etc. It is customary for Scripture to first enumerate the sons of the mistresses together, just as it said in the Seder Vayishlach Yaakov and in the Seder V’eileh Shmoth bnei Yisrael, or else to enumerate them according to the order of their birth, the firstborn according to his birthright and the youngest according to his youth, as Scripture did when they were blessed by Jacob in the Seder Vayechi Yaakov. and in Shmoth, or according to their age, as it did in Vayechi. Ramban is attempting to explain why they are mentioned here after Zilpah’s children. Here, however, because Scripture’s purpose was to enumerate their numbers and to state that with seventy souls they went down to Egypt, it gave precedence to those who were more numerous. This was why Scripture mentioned Rachel among the concubines, and hence it was necessary to mention her with respect, saying, Jacob’s wife, as I have mentioned above.

Ramban (Nachmanides) on the Tanakh — English translation: “Commentary on the Torah by Ramban (Nachmanides). Translated and annotated by Charles B. Chavel. New York, Shilo Pub. House, 1971-1976” (CC BY 4.0). Text via Sefaria.